The Possibilities and Complexities of Organ Development

Organ disease is an ever-growing problem in the United States. Currently, there are nearly 114,000 people on the national transplant waiting list, with an average of twenty people dying every day while awaiting transplant. Perhaps even more staggering is that another person joins the waiting list about every ten minutes, far outstripping the rate at which organs become available.

How Can Organ Research Help?

Organ research, the specific study of a particular organ or organ system, led to the ability to transplant organs in the first place. Nearly fifty years of research took place between the first attempted organ transplant in the 1900s and the first successful transplant in 1954. In the 75 years since then, organ research has addressed many limitations to transplants.

Many of the first transplants failed because the recipient body’s immune system went into overdrive, fighting the new organ as though it was an invading pathogen and eventually rejecting the transplant. Research into methods of suppressing the body’s immune response to new organs has led to a much higher transplant success rate. Similarly, research into the processes that allow organs to preserve their function outside of the human body has led to longer storage times and a higher availability of organs.

Organ Development Is the New Frontier

Although organ research has raised the success rate of organ transplant and ensured the expanded viability of the organs that are available for transplant, the problem of supply and demand continues to haunt those on the transplant list. Simply put, there are not enough suitable donor organs to satisfy the demand for transplants. Fortunately, for those who remain waiting, the field of organ development holds great potential to help people in need of new organs.

Organ development is currently focused on producing bio-engineered, or artificial, organs completely separate from the human body and designed for implantation into people who need new organs. In general, scientists rely on an organic, three-dimensional scaffolding upon which cells specific to that organ can be used to produce a new, identical organ.

The process is complex and involves decellularization of the original scaffold to remove the naturally occurring human or animal cells that may cause an immune reaction and rejection of the organ by the recipient. Then, analysis of the organ and recellularization of the scaffold begin, ideally using cells from the recipient to produce the cells necessary to make up the organ and avoid rejection. One current issue that is the subject of much research is how to develop this tissue in the first place.

The Role of Stem Cells

Currently, cells from other parts of the body are often used to simulate the tissues being replaced on bioengineered organs. While this has been largely successful, certainly organ specific cells would prove much more beneficial. Other research into organs grown artificially from stem cells has proven that organ-specific cells inspire the lowest probability for immune response and rejection.

A stem cell is the body’s most basic cell, in that it can transform into virtually any cell type. Stem cells can be found in embryos and are currently cultured in stem cell lines used solely for laboratory research. A current focus in stem cell research for organ transplant involves the study of how each stem cell differentiates into different tissue types, and thus exits the stem cell phase.

Researchers found that certain proteins affect the gene expression of stem cells as they move along the path to become specific cell types. By adjusting protein stability, researchers can either lock the cell in the stem cell state or release it strategically, potentially allowing it to become specialized as a certain cell type.

What’s Next

Recent success with utilizing stem cells to produce mature liver and heart cells has scientists hopeful that one day, entire mature organs can be produced for transplant. If protein stability research can allow patient-specific, organ-specific artificial and bioengineered tissues to make up these organs, we may soon see the vast waiting list dwindle.